Harnish sat back, the watch swinging like Poe’s pendulum blade from his fingers. “Problems arose. I found that I had but certain windows of opportunity to transmit to my earlier self. Using my own new branch of mathematics, I computed the first date when I might transmit. Can you guess that date, Mackaby?” Mackaby knew but could not speak. Harnish reached out to lay the watch across the arm of Mackaby’s chair. Cringing into the far corner of his seat, Mackaby barely dared to breathe. Apparently oblivious, Harnish rose and began pacing the room. “Today, Mackaby, today. And since you authored my decline, I chose you to share the fruits of my labour. I followed your work and that of your contemporaries. As expected, research emerged four years later refuting your early papers after Amsterda

